In recent years, electronic cameras that convert a subject image into electricity and generate image data are rapidly being widespread. For such an electronic camera, an extension unit of a wireless communication device that transmits photographed image data to the outside is known (refer to non-patent document 1). Thus, for example, in the news field, it is becoming very common that image data photographed at site are transmitted to an editorial department through a communication line network and image data at site are obtained without a time lag.
In addition, in the news field, when photography is performed at a remote location, it may be difficult to properly employ photographers. Thus, when a subject needs to be photographed from many directions, it would be convenient if one photographer could operate a plurality of electronic cameras. With respect to this point, patent document 1 discloses a remote control tripod head system for video camera photography.
However, if a photographer at site cannot identify a person to be photographed, image data of the desired person cannot be obtained. If the number of frames to be photographed is large, the photographer or the editor needs to spend much time to select image data of the desired person. If the photographer at site has photographing orders from many editors, he or she may mistakenly transmit image data to them or forget to photograph desired people. The foregoing non-patent document 1 does not disclose any countermeasures against such problems.
The technique disclosed in the foregoing non-patent document allows one photographer to operate a plurality of cameras to photograph a subject from many directions. However, a slave camera that the photographer does not directly operate may not correctly frame a subject. Thus, there is yet room for improvement in the related art.
Patent document 1: Japanese Unexamined Patent Application Publication No. HEI 11-95313
Non-patent document: Digital single-lens reflex camera “D2H” catalog—Wireless Transmitter WT-1, NIKON CORPORATION, Sep. 15, 2003, p. 10